So they have once again moved the location where 3rd-party plugins are stored in Notepad++. They are now stored in:

%PROGRAMDATA%\Notepad++\plugins\PluginName\
This is generally C:\ProgramData or what is also known as %ALLUSERSPROFILE%.

The thinking here is that you are almost certainly going to want plugins installed for all user accounts on your system that use Notepad++. Other settings and customizations to either the plugins or Notepad++ in general will be stored in the %APPDATA% folder for each user account, as always.

The installer for RainLexer will remove any old, unneeded versions of the plugin from old locations.

This rollout of how plugins are managed in Notepad++ is not their finest hour. Not well tested, no backwards compatibility, no notice given to plugin authors, didn't measure twice and cut once. Hopefully things have settled down to a permanent state now.

eclectic-tech, this is going to impact your Snippets thing as well. Fortunately they will simply have to re-install the Snippets plugin from the Plugin Manager functionality in Notepad++, and all will be well. The sql database with your Rainmeter snippets will remain where it is and no change needs to be made. If they want to be anal-retentive (I would), they can simply remove the entire %LOCALAPPDATA%\Notepad++ folder, as Notepad++ no longer uses that ..AppData\Local structure at all, which by the way, it never should have used. Plugins are all in ..ProgramData, and settings are all in ..AppData\Roaming.

The config files for the plugins remain in %APPDATA%\Notepad++\plugins\config

This rollout of how plugins are managed in Notepad++ is not their finest hour. Not well tested, no backwards compatibility, no notice given to plugin authors, didn't measure twice and cut once. Once again, we can hope that things have settled down to a permanent state now.